As a fluid controller of a valve opening and closing timing control apparatus, US 2013-0118622 A (Reference 1) discloses a technology in which a control piston is accommodated in a housing so that a check valve is provided in a path, through which a hydraulic oil is supplied to the control piston, to prevent backflow of the hydraulic oil.
In Reference 1, the check valve is configured to have a plate formed with an opening and a valve body supported by a plate-shaped elastic member so as to enable closing of the opening.
In addition, US 2015-0300212A (Reference 2) discloses a technology in which a check valve having the same configuration as that of Reference 1 and a relief valve are provided parallel to each other.
In addition, JP 2015-145672A (Reference 3) discloses a technology in which, as a hydraulic valve disposed coaxially with a rotation axis of a valve opening and closing timing control apparatus, a valve piston is accommodated in a valve housing, an electromagnetic linear actuator is provided to actuate the valve piston, and a band-shaped check valve is provided on a portion of an area surrounding the valve piston.
When a valve unit is disposed coaxially with the rotation axis of the valve opening and closing timing control apparatus as in the inside of a connecting bolt of the valve opening and closing timing control apparatus, since the distance between the valve unit and an advanced angle chamber or a retarded angle chamber, which is formed between a driving side rotator and a driven side rotator, may be reduced, the pressure loss of a flow path is reduced, which realizes an operation with good responsiveness.
In addition, in this configuration in which the valve unit is disposed coaxially with the rotation axis, it is reasonable to have the check valve integrally with the valve unit, as described in References 1 to 3.
However, as represented in References 1 and 2, in the check valve having the configuration in which the plate formed with the opening and the valve body capable of closing the opening are disposed at positions spaced apart from the rotation axis, upon the assembly of the check valve, it takes time to appropriately set these positions. In addition, when the plate and a member having the valve body are integrated in advance in order to solve this problem, the number of assembling processes is increased.
Thus, a need exists for a valve opening and closing timing control apparatus which is not susceptible to the drawback mentioned above.